Asbestos-plastic film laminates

ABSTRACT

An asbestos-plastic film laminate useful as a strippable, nonflammable wallpaper and which is dimensionally stable and mildew resistant, is made up of a first sheet of asbestos having a thickness of about 0.010 inch, a second sheet of asbestos built up and formed directly on said first sheet of asbestos, said second sheet of asbestos having a thickness of about 0.002 inch and a plastic film, e.g. a polyvinyl chloride film, applied to and affixed to the other side of said first sheet of asbestos, said plastic film having a thickness in the range from about 0.001 to about 0.003 inch.

ilnited States Patent Breiner Nov. 6, 1973 [54] ASBESTOS-PLASTIC FILMLAMINATES 3,511,748 5/1970 Heeb et a1. 161/205 [7 Inventor: Richard C ene tbom a. 3,554,861 1/1971 Ermenc et a1. 161/205 [73] Assignee: NicoletIndustries, Inc., Ambler, Pa. Primary ExaminerGeorge F. Lesmes AssistantExaminer-S. Silverman [22] Flled' 1971 Attorney-R0bert S. Dunham, P. E.Henninger, Lester [21] Appl. No.: 117,543 W. Clark, Gerald W. Griffin,Thomas, P. Moran, Howard J. Churchill, R. Bradlee Boal, Christopher C.52 us. (:1 161/205, 161/193, 161/165, Scobey and Henry Burke 161/403,161/406, 156/306, 156/308 51 1111.0 B32b 13/04, B32b 19/08 ABSTRACT (ItSearch An asbestos plastic laminate useful as a trippable 161/406non-flammable wallpaper and which is dimensionally stable and mildewresistant, is made up of a first sheet References Cited of asbestoshaving a thickness of about 0.010 inch, a UNlTED STATES PATENTS secondsheet of asbestos built up and formed directly 2,272,144 2 1942 Allen161 406 Said first Sheet of asbestos Said Second Sheet of 3,188,2636/1965 Pflaumer 161/205 besws having a thickness of about 01102 inch anda 3,619,354 11/1971 Woolery 161/205 plastic film, e.g. a polyvinylchloride film, applied to 2,938,822 5/1960 Nelson 161/205 and affixed tothe other side of said first sheet of asbes- 292,037 H1384 Nagel 161/403tos, said plastic film having a thickness in the range 1,523,634 1/1925Crabbs 161/403 from about 0001 to about 0003 inch. 2,638,638 5/1953McBride 161/406 3,332,830 7/1967 Tomlinson et a]. 161/403 8 Claims, 3Drawing Figures WEAK ASBfJfQS/GAASJ PLJ/ STRONG ASE F5775 PLVASBESTOS-PLASTIC FILM LAMINATES This invention relates toasbestos-plastic film laminates. In accordance with one embodiment thisinvention is directed to a strippable, substantially nonflammable,asbestos-plastic film laminate useful as wallpaper, as upholstery inautomobiles, airplanes, etc. In accordance with another embodiment thisinvention is directed to the production of an asbestos-plastic filmlaminate which is substantially non-flammable, dimensionally stable andmildew resistant, properties particularly desirable in a strippablewallpaper.

Strippable wallpapers have been made from cellulosic, synthetic andvegetable fibers. Patterns are applied to the wallpaper and thewallpaper is affixed or adhered to the wall to be covered by means of asuitable paste or contact adhesive. When the applied strippablewallpaper is no longer wanted the wallpaper is removed by pulling orstripping the wallpaper from the wall without requiring the use ofisteam or moisture. When the strippable wallpaper is removed a thinfibrous ply is usually left upon the wall and upon this ply a newwallpaper can be applied.

Conventional strippable wallpapers are flammable, not dimensionallystable, susceptible to moisture, humidity variations and mildew.Further, strippable wallpapers available heretofore have not beenuniformly strippable.

It is an object of this invention to provide an asbestosplastic filmlaminate useful as an upholstery material or as a strippable wallpaper.

It is another object of this invention to provide a dimensionallystable, mildew resistant asbestos-plastic film laminate.

Still another object of this invention is to provide a method of forminga multi-ply asbestos sheet structure wherein one asbestos-containingsheet is readily strippable from another asbestos-containing sheet incon tact therewith.

Still another object of this invention is to provide a method for theproduction of an asbestos-plastic film laminate useful as a strippablewallpaper.

How these and other objects of this invention are achieved will becomeapparent in the light of the accompanying disclosure made with referenceto the accompanying drawings wherein:

FIG. 1 schematically illustrates a process for the manufacture of a twoply asbestos sheet structure characterized in that one of the asbestosplies is readily strippable or removable from the other asbestos ply incontact therewith;

FIG. 2 schematically illustrates the formation of an asbestos-plasticfilm laminate in accordance with this invention wherein the multi-plyasbestos sheet structure produced by the process illustrated in FIG. 1is coated with or has applied thereto a plastic film and wherein;

FIG. 3 schematically illustrates the asbestos-plastic film laminatestructure produced by the process illustrated in FIG. 2.

An asbestos-plastic film laminate in accordance with this invention ismade up of a first sheet of asbestos, such as a first sheet of asbestospaper, a plastic film applied to and affixed to one side of said firstsheet of asbestos paper and a second sheet of glass fiber or asbestos,such as a second sheet of asbestos paper, applied to and affixed to theother side of said first asbestos sheet.

The first sheet of asbestos has a thickness substantially greater thanthe thickness of the second sheet of asbestos. For example, the firstsheet of asbestos would have a thickness of about 0.010 inch, such as athickness in the range from about 0.005 inch to about 0.020 inch whereasthe second sheet of asbestos would have a relatively small thickness ofabout 0.002 inch, such as a thickness in the range 0.0005 inch to about0.005 inch.

The plastic film applied to the first sheet of asbestos would have athickness of about 0.002 inch, such as a thickness in the range fromabout 0.001 inch to about 0.010 inch. Advantageously, the second sheetof asbestos employed in the manufacture of the asbestos-plastic filmlaminate in accordance with this invention might comprise only glassfibers as a substitute for the ashestos fibers. It is desirable,however, for the second asbestos sheet to be made up of an admixture ofasbestos fibers and glass fibers or admixtures of asbestos and mineralfibers (mineral wool) or asbestos and diatomaceous earth(,Iohns-Manville CELITE), or asbestos and finely ground vermiculite(Verxite FCF, Zonolite Div., W. R. Grace Co.). The second asbestos sheetof the asbestos-plastic film laminate in accordance with this inventionprovides or forms a weak strippable bond with the first sheet ofasbestos.

In the preparation of the asbestos sheets, such as the sheets ofasbestos paper employed in the manufacture of the asbestos-plastic filmlaminates, the asbestos sheet or paper requires some binder to providestrength and satisfactory handling properties to the resulting asbestossheet. Asbestos paper formed without a binder or with a low bindercontent, such as a binder content in the range from about 0.5 to about 2percent by weight, is usually too weak and provides insufficientsubstance or body for handling and would permit bleed-through of theadhesive if the resulting asbestos sheet or paper were employed in themanufacture of an asbestos-plastic film laminate used as a wallpaper. Onthe other hand, an asbestos sheet of paper having a high binder content,such as a binder content above about 20 percent by weight, would yieldan asbestos sheet having increased flammability. In essence, therefore,in

the production of an asbestos-plastic film laminate in accordance withthis invention there is produced a combination of sheets, one sheethaving a high binder content relative to the other sheet in contacttherewith so as to provide an asbestos sheet with good handlingproperties and strength and which would prevent the bleed-through of anyadhesive and the other asbestos sheet having a relatively low bindercontent to yield a ture. The plastic film may be provided with a printedpattern or may be a clear, transparent plastic film in which instancethe underlying asbestos sheet would be printed with a pattern. Plasticfilms which are useful in the manufacture of asbestos-plastic filmlaminates in accordance with this invention include the variouspolyolefin films, such as polyethylene, polypropylene, the variouspolyvinyls, including polyvinyl chloride and polyvinylidene chloride.Acrylic films may also be used but polyvinyl chloride and polyvinylideneare preferred for non-burning characteristics.

The plastic film may be adhered to the underlying asbestos sheet in themanufacture of an asbestos-plastic film laminate in accordance with thisinvention by the application of pressure or heat and pressure, such asby calendering a plastic film onto an asbestos sheet. The affixing of aplastic film to an underlying asbestos substrate is particularlyconvenient in the practice of this invention when the plastic film isrelatively soft, i.e. has a substantial plasticizer content, so that theplastic film can be readily, upon the application of pressure, forcedinto the interstices of the underlying asbestos substrate.Alternatively, the plastic film may be affixed to the underlyingasbestos sheet by means of an adhesive, such as a wheat paste, or achemical adhesive, such as a urethane adhesive or a rubber cement or bymeans of a polyvinyl chloride or a polyacrylonitrile adhesive orneoprene-containing adhesive. Adhesive bonding of film to asbestosgenerally provides the strongest bond.

Referring now to the drawings which schematically illustrate processesemployed in the practice of this invention and the resulting product,FIG. 1 shows an asbestos paper-making operation for the manufacture ofthe two plies of asbestos sheet or paper employed in the fabrication ofan asbestos-plastic film laminate in accordance with this invention. Theasbestos papermaking operation illustrated in FIG. 1 employs aconventional Fourdrinier machine comprising an endless belt moving onrollers 11 in the direction indicated by the arrows. A press sectionmade up of a plurality of press rollers 12 disposed transversely of andon both sides of belt 10 is employed to dry the asbestos web carried ontop or outside of belt 10.

In operation, in the preparation of the asbestos sheets or plies inaccordance with this invention a dual or two stock system is employed.One system, System A, is prepared in mixing vat 14 and supplied to tank15. Tank 15 is provided with a plurality of asbestos papermaking rolls16 in sections thereof defined by dividers 17. Paper-making rolls rotateas indicated by the arrows and a web of asbestos is formed thereon. Asthe web is formed and brought into contact with belt 10 the formed webis transferred from respective roll 16 to belt 10. in this manner asincreasingly thick asbestos web or layer of asbestos paper is built upon belt 10 as it moves along in contact with rolls 16.

The stock or furnish produced in vat 14 is in accordance with standardasbestos paper-making techniques and formulation. The solids componentsof the furnish or system are made up of highly cleaned chrysotileasbestos fiber, e.g. 7 Grade PBS asbestos sold by Johns Manville Corp.or Asbestos Corporation fiber 431EX7D in an amount in the range 80-90percent by weight of the solids content of the furnish. A whiteningagent is desirably incorporated in the furnish, such as finely dividedtitanium dioxide, e.g. anatase titanium dioxide, Ti-Pure, sold by E. l.duPont de Nemours Co., Inc. Additionally, there is incorporated in thefurnish an amount of organic binder in the range 2-18 percent by weight,such as polyvinyl chloride binder, e.g. Geon 450-X23 sold by B. F.Goodrich Chemical Co. The web of asbestos paper formed on belt 10 fromthe system A furnish provides the strong asbestos ply or sheet, e.g. theasbestos sheet having the final thickness of about 0.010 inch of thefinished asbestos-plastic film laminate in accordance with thisinvention. The asbestos sheet or ply derived from the System A furnishmakes up about to percent by weight of the total asbestos sheeteventually formed on belt 10.

The terminal paper-making stage of the asbestos paper-making machineillustrated in FIG. 1 is supplied with a System B furnish from vat 18.The asbestos paper formed on paper-making roll 16 derived from System Bfurnish is applied to the asbestos web on belt 10 as the last asbestosweb or ply thereon. The web formed from the System B furnish and lastapplied onto belt 10 comprises the weak, thin ply of glass and/orasbestos paper making up the product asbestos-plastic laminate and formsthe strippable weak portion thereof. The web formed from the System Bfurnish contributes to about 10-20 percent by weight of the final webformed on belt 10. The System B furnish, based on the solids content, ismade up of 0-90 percent highly cleaned chrysotile asbestos fiber, e.g.Canadian Grade 5, 6 or 7 chrysotile asbestos fiber, 0-90 percent glassfiber, e.g. SG glass fiber sold by Johns Manville or milled glass fibersold by Owens Coming. The solids making up the System B furnish alsocontain 0-1 percent by weight whitening agent, such as titanium dioxideand l-S percent by weight of a suitable binder, such as polyvinylchloride. Other whitening agents which may be employed in themanufacture of the furnishes of System A or System B include calciumcarbonate and calcium silicate. Relatively non-flammable agents orbinder which may be employed in the furnishes of Systems A or B includepolyvinylidene chloride and chloroprene. If necessary, and as may berequired, stablizing agents and antioxidants for the binders might alsobe incorporated in the furnish of Systems A and B.

The furnishes of Systems A and B having the abovedescribed solidscomposition are prepared in accordance with standard asbestospaper-making practices. The solids content of the furnishes of Systems Aand B comprise about 0.5-5.0 percent by weight of the furnish, theremainder being water. Usually the solids content of the furnish is inthe range 1.5-3.5 percent by weight.

The web of asbestos formed on belt 10 passes through the press sectionthereof between press rolls 12 which serve to remove a substantialamount of water therefrom and the resulting asbestos web, now having asubstantially reduced water content passes onto the drying and windingsection as illustrated.

As mentioned hereinabove the finished web moving off belt 10 for dryingand winding is made up of an asbestos web or ply derived from the SystemA furnish and a ply derived from the System B furnish. The web or plyderived from the System A furnish contributes to a major amount thefinal thickness of the finsihed web, e.g. about 0.010 inch. The web orply derived from the System B furnish contributes only a minor amount tothe thickness of the finished web, such as a thickness of about 0.002inch.

Referring now to FIG. 2 of the drawings, after the asbestos web formedin the manner schematically illustrated in FIG. 1 has been dried andwound and calendered to provide a smooth surface, the web is unwoundfrom roll 20 and passed through an adhesive application stationgenerally indicated by reference numeral 21 wherein a suitable adhesive,such as urethane adhesive, e.g. Cyanprene Latex X5 sold by AmericanCyanamide, is applied to the top surface thereof. Thereupon a film ofplastic, such as polyvinyl chloride plastic, from roll 22 is pressedonto the adhesive coated asbestos web as the plastic film and web movesbetween rolls 24 which serve to apply pressure to the thus-joined websof plastic and asbestos. The resulting asbestos-plastic film laminatethen moves past roller 25 onto take-up roll 26.

FlG. 3 schematically illustrates the make-up of the resultingasbestos-plastic laminate. As indicated, asbestos or glass fiber sheet30 formed on the paper-making equipment from the System B furnish, isthe weak strippable ply. The other asbestos ply 31 formed on theasbestos paper-making machine from the System A furnish comprises therelatively strong asbestos ply of the finished asbestos-plastic filmlaminate. The plastic film 32 which may be printed or patterned impartsabrasion and wear resistance and washability to the resulting structure,such as when the resulting asbestos-plastic film laminate structure isemployed as a wall coating. When employed as a wall coating theasbestos-plastic film laminate is adhesively secured or applied on theasbestos side to the surface to be covered.

When it is desired to remove the coating from the covered surface thecoating is simply mechanically stripped or removed therefrom. Uponmechanical removal or stripping, the plastic film and the relativelystrong asbestos ply derived from the System A furnish are removed sincethe asbestos and/or glass fiber ply derived from the System B furnishand in immediate contact with the substrate or surface which has beencovered breaks, thereby permitting the simultaneous removal of theplastic film and the System A furnish asbestos ply.

The following examples are illustrative of the practice of thisinvention.

EXAMPLE NO. 1

An asbestos web having a thickness of 0.010 inch was formed from aSystem A furnish made up of a solids content of 84 percent by weightchrysotile asbestos fibers, percent by weight polyvinyl chloride and 1percent by weight titanium dioxide. A second asbestos web was thenformed on this first asbestos web; the second asbestos web having athickness of 0.002 inch was formed on the above 0.010 inch thickasbestos web from a System B furnish having a solids composition of 75percent by weight chrysotile asbestos fibers, 23 percent by weight glassfiber and 2 percent by weight polyvinyl chloride. The resulting formedwebs as a single sheet were then dried by conventional asbestospapermaking techniques and a film of polyvinyl chloride having athickness of 0.002 inch was applied by means of urethane adhesive ontothe System B furnish side, i.e. to the exposed side of the asbestos plyhaving a thickness of 0.010 inch.

EXAMPLE NO. 2

An asbestos-plastic film laminate was prepared in the manner describedin connection with Example No. 1 save that the asbestos ply having athickness of 0.002 inch was derived from a System B furnish having asolids content of 98 percent by weight asbestos fiber and 2 percent byweight polyvinyl chloride.

EXAMPLE NO. 3

An asbestos-plastic film laminate was prepared in accordance with themethod of Example No. 1 save the 0.010 inch and 0.002 inch asbestos plyportions were each derived from a furnish having the solids compositionof 96 percent by weight asbestos fiber and 4 percent by weight polyvinylchloride.

EXAMPLE NO. 4

An asbestos-plastic film laminate was prepared in accordance with themethod of Example No. 1 save the 0.010 inch and 0.002 inch asbestos plyportions were each derived from a furnish having the solids compositionof 84 percent by weight asbestos fiber, 15 percent by weight polyvinylchloride and 1 percent by weight titanium dioxide.

As will be apparent to those skilled in the art in the light of theforegoing disclosure, many modifications, alterations and substitutionsare possible in the practice of this invention without departing fromthe spirit or scope thereof.

I claim:

1. An asbestos-plastic film laminate useful as a strippable,dimensionally stable, mildew resistant, nonflammable wallpaperconsisting essentially of a first sheet consisting essentially ofasbestos fibers and an organic binder therefor, a plastic film having athickness in the range 0.00l0.0l0 inch applied to and affixed to oneside on said first sheet of asbestos fibers and a second sheetconsisting essentially of glass fibers and/or asbestos fibers and anorganic binder therefor applied to and affixed to the other side of saidfirst sheet, said first sheet having a thickness in the range 0.005-0.02inch, said second sheet having a thickness in the range from about0.0005 inch to about 0.005 inch and the organic binder content in saidsecond sheet being present in an amount up to about 5 percent by weightand the organic binder in said first sheet being present in an amount upto about 20 percent by weight, the amount of organic binder in saidfirst sheet being greater than the amount of organic binder in saidsecond sheet.

2. An asbestos-plastic film laminate in accordance with claim 1 whereinsaid plastic film is polyvinyl chloride.

3. An asbestos-plastic film laminate in accordance with claim 1 whereinsaid plastic film is polyethylene.

4. An asbestos-plastic film laminate in accordance with claim 1 whereinsaid plastic film is polyvinylidene chloride.

5. An asbestos-plastic film laminate in acordance with claim 1 whereinsaid first sheet of asbestos comprises 80-90 percent by weight asbestosfiber, 1-3 percent by weight whitening agent and 2-18 percent by weightof an organic binder.

6. An asbestos-plastic film laminate in accordance with claim 5 whereinsaid whitening agent is titanium dioxide and wherein said binder ispolyvinyl chloride.

'7. An asbestos-plastic film laminate in accordance with claim 1 whereinsaid first sheet of asbestos comprises about 84 percent by weightasbestos fiber, about 15 percent by weight polyvinyl chloride as binderand about 1 percent by weight titanium dioxide as whitening agent,wherein said second sheet comprises 23 percent by weight glass fiber,about percent by weight asbestos fiber and about 2 percent by weightpolyvinyl chloride as binder.

8. An asbestos-plastic film laminate in accordance with claim 7 whereinsaid plastic film is affixed to said first sheet of asbestos by meansofan adhesive.

1: i t t

2. An asbestos-plastic film laminate in accordance with claim 1 whereinsaid plastic film is polyvinyl chloride.
 3. An asbestos-plastic filmlaminate in accordance with claim 1 wherein said plastic film ispolyethylene.
 4. An asbestos-plastic film laminate in accordance withclaim 1 wherein said plastic film is polyvinylidene chloride.
 5. Anasbestos-plastic film laminate in acordance with claim 1 wherein saidfirst sheet of asbestos comprises 80-90 percent by weight asbestosfiber, 1-3 percent by weight whitening agent and 2-18 percent by weightof an organic binder.
 6. An asbestos-plastic film laminate in accordancewith claim 5 wherein said whitening agent is titanium dioxide andwherein said binder is polyvinyl chloride.
 7. An asbestos-plastic filmlaminate in accordance with claim 1 wherein said first sheet of asbestoscomprises about 84 percent by weight asbestos fiber, about 15 percent byweight polyvinyl chloride as binder and about 1 percent by weighttitanium dioxide as whitening agent, wherein said second sheet comprises23 percent by weight glass fiber, about 75 percent by weight asbestosfiber and about 2 percent by weight polyvinyl chloride as binder.
 8. Anasbestos-plastic film laminate in accordance with claim 7 wherein saidplastic film is affixed to said first sheet of asbestos by means of anadhesive.